Generally, when a pair of contacts in an open contact state are closed (close contact) at a certain speed in a power switchgear and a switchgear, bounce (hereinafter, referred to as chattering) is generated between the contacts. A voltage is applied between the contacts; and therefore, arc is generated for each chattering and contact surfaces become coarse or waste away, so that there is a demerit that contact resistance unnecessarily increases.
Furthermore, a problem exists that when duration time of the chattering is long, the contacts fuse; and therefore, the duration time of the chattering needs to be shortened as much as possible.
In a switching apparatus of a known art shown in FIG. 8, a vacuum valve 1 houses a fixed contact 10 and a movable contact 11. The vacuum valve 1 is fixed to a fixed conductor 6 and the fixed conductor 6 is supported by a plurality of overlapped coned disc springs 63. The coned disc springs 63 are of an elastic body and the plurality of coned disc springs are overlapped and stacked.
Therefore, the coned disc springs 63 are minutely movably moved and a plurality of minute collisions are repeated to consume kinetic energy with respect to the bounce (chattering) generated at the time when the movable contact 11 in the vacuum valve 1 is operated to collide with the fixed contact 10. In doing so, the chattering is suppressed. Incidentally, the height of the coned disc springs 63 is set so as to obtain a predetermined buffering force by adjusting the clamping force of fixing bolts 62 according to the switching apparatus with respect to a load which makes the movable contact 11 operate so to be in a close contact state with the fixed contact 10.    [Patent Document 1] Japanese Unexamined Patent Publication No. 2006-164654